This invention relates to a mechanical prosthesis which provides erections for human males who suffer the dysfunction of erectile impotence.
Various implantable devices for achieving penile erection have been developed. These devices are classified as either mechanical or the more recently developed inflatable devices. The inflatable devices involve an implantable hydraulic fluid transfer system where the corpora are inflated and deflated at will in an attempt to closely approximate the physiological state of the penis in its erect and flaccid states.
The inflatable prosthesis appear to have excellent potential; however, at present, they have shortcomings. For example, the pump and release valves are frequently located in the scrotum, which is one of the body's sites most disposed to post-operative discomfort and infection. Some inflatable devices require one or more minutes of pumping to inflate. Furthermore, extensive surgery is required and both hydraulic and mechanical failures have been experienced.
The mechanical prosthesis were originally stiff rods designed to be implanted in the corpora cavernosa to attain penile erection. Although this system provides a longer, thicker and stiffer erectile state, the flaccid state is no longer achievable--the patient has a permanent erection. Furthermore, fractures during intercourse have been experienced with the stiff rods. After fracture the penis is frail and no longer functional for intercourse.
Flexible rods have been developed to overcome the shortcomings of the stiffer rods. Timm in U.S. Pat. No. 3,987,789 describes a prosthesis including an elongated malleable rod portion housed within a generally tubular physiologically inert plastic body. The malleable rod portion enables the prosthesis to be conformed to a variety of shapes by bending or twisting. During intercourse the prosthesis will maintain the penis in a erectile state and afterwards the penis may be positioned and maintained by the user in a convenient, comfortable position. Flexible rods of this type have been successful, however the penis still does not feel physiologically normal. The penis does not bend freely as it naturally does in the flaccid state. Moreover, one of the most annoying problems of the malleable rod implant is its tendency to creep up, and, consequently must frequently be repositioned.
The latest concept in mechanical implants rods comprised of hinged segments or links. The hinged rods allow the penis to bend more freely.
Barrington in U.S. Pat. No. 4,151,840 describes a hinged mechanical penile prosthesis, which is comprised of a plurality of independent segments or links enclosed in a pre-stretched tubular sheath. The sheath maintains the segments in link-to-link contact, so that on straightening a concave end of a segment mates a convex end of an adjacent segment whereby the segments are aligned into a straight rod, resulting in an erect penis.